This is a pretty good story about a small plane ditching:

http://www.equipped.org/1199ditch.htm

Crucial to the story is that the pilot notified the coast guard by radio as soon as the engine trouble started (hours before the engine actually stopped). That seems to be what's missing from that ELT picture. I defer to the wisdom of you old timers about whether ELT should be activated when the plane's occupants are already probably squashed.

I thought also that all planes were supposed to have "black boxes" that broadcast a locator signal. Is that just for big airliners?